The present invention relates in general to the field of mechanical devices for connecting an aircraft mounted exhaust system to a gas turbine engine. More particularly, one embodiment of the present invention defines a coupling having pins extending from the exhaust system that are received within recesses formed in a collar mounted to the gas turbine engine to allow relative movement between the components while maintaining the gas turbine engine connected to the aircraft mounted exhaust system. Although the coupling system was developed for an aircraft mounted exhaust system, certain applications may be outside of this field.
It is well known that a gas turbine engine is often utilized to provide the motive force for propelling the aircraft through the air. Generally, the gas turbine engine is attached to a portion of the aircraft structure, such as the wing or nacelle structure. In some aircraft designs, the gas turbine engine is mounted to the aircraft structure so as to allow relative motion in several planes including side-to-side, up-and-down, front-to-rear, and some combination of the three. Often, the movement in one of the possible planes of motion is quite severe while the movement in the other planes of motion is limited. For example, the T56-A15 engine manufactured by Rolls Royce Allison of Indianapolis, Ind. and utilized on the Lockheed C-130 Aircraft is securely mounted by two stout rubber mounts at the forward end of the engine and one mount at the top rear of the engine. This mounting configuration allows the rear of the engine to move laterally several inches while its front-to-rear and up-and-down motion is inhibited by the mounting structure to a fraction of an inch. In the Lockheed C-130 Aircraft, the exhaust system is relatively lightweight and mounted directly to the engine and allowed to move with the engine.
In certain aircraft designs, the exhaust system is heavier than the gas turbine engine can support under dynamic conditions. A generally accepted design practice is to support a significant portion of the weight and dynamic load of the exhaust system from the aircraft wing or nacelle structure. In these designs, it is desirable that a mechanical device connects between the gas turbine engine and the exhaust system to allow for substantial motion between the engine and exhaust system in one dimension while limiting the amount of motion in the other dimensions. One prior art-coupling scheme consists of a complex system of overlapping seals and springs that are coupled to the gas turbine engine and the exhaust duct with mounting rings. The overlapping seals allow motion in up-and-down and side-to-side directions by the slippage of the seals on each other. Front-to-back motion is accommodated by the springs as the unit expands and contracts with the relative motion.
Heretofore, there has been a need for a coupling for connecting a gas turbine engine to an aircraft mounted exhaust system. The present invention satisfies this need in a novel and unobvious way.